By right-click on the template file and choose “Run Custom Tool” the entity classes will be regenerated to reflect the latest changes to the model. As the context by default expects the entity classes to be in the same namespace, add a using statement for their new namespace to the Model. Finally, you need to add a reference from the DAL project to the domain model project in order for it to compile.In an EF-based application a context is responsible for tracking changes that are made to the entities after they have been loaded from the database.Thus you should always keep your LINQ queries inside of the repository when using EF in a disconnected scenario such as in an N-tier application. However, in an N-tier application entity objects are usually disconnected meaning they are not being tracked by a context as the data is fetched using one context, returned to the client where there is no context to track changes and then sent back to the server and persisted back to the database using another instance of the context.
On the server side, things will get easier if you decide to not support graphs.
In this case you could expose an Add method and an Update method for each entity type and these methods would only operate on a standalone instance rather than a graph of entities. It is all about setting the state of the passed in entity object.
Each of the methods for reading data from the database in the concrete sample implementation of the using Mm. A graph of entities is a number of entities that reference each other.
For example, when you want to insert a new object is the root entity.
An entity can be in one of five states as defined by the : the entity is not being tracked by the context at all.
When the context’s Save Changes method is called it decides what to do based on the entity’s current state.This post is about how you can develop a generic data access layer (DAL) with full CRUD (Create, Read, Update and Delete) support using Entity Framework 5 with plain old CLR objects (POCOs) and short-lived contexts in a disconnected and stateless N-tier application.Entity Framework (EF) is Microsoft’s recommended data access technology when building new . It is an object-relational mapping framework (ORM) that enables developers to work with relational data using domain-specific objects without having to write code to access data from a database.getting employees associated with a department in this case. When using short-lived contexts like this, you should disable lazy loading.Eager loading uses the Include method on the to load child entities and will issue a single query that fetches the data for all the included entities in a single call. If you don’t an exception saying the context has been disposed will be thrown whenever a non-initialized navigation property is accessed from anywhere outside the context’s scope. Lazy loading and dynamic proxy creation is turned off for all entities in a context by setting two flags on the Configuration property on the When it comes to persisting changes to the database you need to decide whether your CUD methods should accept an entire graph of entities or only a single root entity to be passed in.As databases within enterprise environments are generally designed and maintained by database administrators (DBAs) rather than developers, this post will use the database first option where the EDM becomes a virtual reflection of a database or a subset of it.